Storage phosphorus film is read by photoelectrically detecting an image formed by scanning with stimulating radiation. An example of such scanner/reader is disclosed in U.S. Pat. No. 4,789,782 to O'Hara. Typically the cassette is fed to the reader either individually, or by an autoloader such as that described U.S. application Ser. No. 07/981,719 filed Nov. 25, 1993 entitled "Autoloader for Photos or Other Cassettes and/or Pallets Containing a Photosensitive Material", which is filed concurrently herewith and which is also incorporated herein by reference. The autoloader provides cassettes in seriatim to the reader. Typically, some type of mechanism is used to remove the photosensitive material from within the cassette. The autoloader allows a plurality of individual cassettes to be placed therein for automatic supplying to the reader, thus freeing the operator to accomplish other duties. With such autoloaders it is important to provide a mechanism to properly present the cassette at the same place each time. Likewise, the mechanism in the reader must be able to remove the photosensitive material from the cassette and return it to the cassette after it has been properly scanned and erased. The problem with such prior art devices is that there must be extreme accuracy in order for the mechanism within the reader to properly remove the photosensitive element from the cassette. Typically, in order to accomplish this, it is necessary to precisely place every cassette in the exact same position so that the extractor mechanism in the reader can properly align with the latching mechanism provided in the cassette. While prior art devices can provide the cassettes in generally the same location, it is extremely difficult to position the cassette always in the same position. This is made even more difficult due to the normal wear of the positioning mechanism in the autoloader. Additionally, manufacturing tolerances in the cassette may result in the latching mechanism not being located precisely in the same position from one cassette to the next. Thus, variations in the presentation of the cassette and latching mechanism to the reader can occur from a number of factors. In order for the reader to operate effectively with the autoloader, it is important that the unlatching mechanism used to unlatch the cassette and remove the photosensitive material can be accurately aligned with the cassette, not only for removal, but also for returning of the photosensitive material back into the cassette. Prior art devices, in order to attempt a solution to the accurate positioning of the cassette, have had to resort to complex or expensive positioning and aligning mechanisms in order to accurately align the extraction mechanism with the latching mechanism on the cassette.
Applicants have invented a reader which utilizes a relatively simple mechanism for unlatching and latching of the cassette, that is able to accurately locate the cassette even if the cassette is not presented exactly in the same position each time a cassette is fed to the reader and can also take into consideration normal manufacturing tolerances of the cassette. This and other advantages will be set forth in the detailed description of the present invention.